Poland risks isolation in the European Union after its rightwing government failed in its bitter campaign to derail the re-election of its own citizen Donald Tusk as the bloc's president.

"Alone in the EU" and "Tusk won 27 to 1" read headlines splashed across the front pages of major liberal and centrist newspapers in Poland on Friday, while a high-circulation tabloid declared Tusk "King Donald II".

The bloc's leaders voted by 27 to one at a Brussels summit to give former Polish premier Tusk a new two-and-a-half-year mandate -- with only Poland's current Prime Minister Beata Szydlo voting against.

Szydlo, whose eurosceptic Law and Justice (PiS) party has nursed a long and bitter enmity with the centrist Tusk, on Friday also blocked the summit's final statement in response.

Her government accuses Tusk of having "brutally violated" the rule of "political neutrality" by becoming involved in domestic political disputes.

Since winning power in October 2015 elections, Szydlo's populist administration has pushed through a string of controversial reforms that triggered mass protests at home and an EU threat of sanctions over rule of law violations.

"It's obvious that Warsaw is isolated and has no allies in Europe," the daily said in an acerbic editorial.

Gazeta Wyborcza meanwhile observed that "the open war against the EU will have detrimental consequences for Poland", particularly in terms of the future EU budget and regional policy.

"If (PiS party leader Jaroslaw) Kaczynski forces the government to get angry with the EU, it's not the EU that will lose but Poland," it said.

Although he holds no office other than being an MP, Kaczynski is Poland's de facto most powerful politician.

"Poland's European policy under the PiS is a total failure. It has positioned itself as a complete outsider," Professor Radoslaw Markowski, a political scientist and member of Poland's Academy of Sciences told AFP.

Remarks by other EU leaders appear to back up the criticism levelled at the government on the home front.

"It's not acceptable that one member says 'I don't want that', and then the other 27 are paralysed," said Luxembourg Prime Minister Xavier Bettel as he arrived for the talks Friday.

Bettel also accused Szydlo of "not acting like an adult".

Austrian Chancellor Christian Kern was more circumspect, saying that "it's not in Poland's interest to pull out of the process of joint discussions".

Meanwhile, French Foreign Minister Jean-Marc Ayrault pointed to "domestic politics" as the real reason behind the clash and disagreed with PiS allegations that Tusk lacked neutrality.

Kaczynski called political arch-rival Tusk "Germany's candidate" before the vote, warning that his re-election would sow crisis in the EU.

Poland also accused Germany of forcing its will on the EU after Tusk's re-election, with Foreign Minister Witold Waszczykowski saying: "We know that this is now a Union under Berlin's diktat."

Adding to the bad blood, Kaczynski has long accused Tusk of "moral responsibility" for the death of his brother Lech, then president, in an air crash in Russia in 2010. Tusk was prime minister at the time.

"They live in two completely different universes," liberal Polish MEP Roza Thun told AFP of the two politicians.

"Kaczynski isn't a democrat -- he has no idea about compromise, cooperation, community, and he regards political rivalry as war rather than dialogue," Thun added.

"Tusk beat him several times as a political rival on the Polish domestic scene. Since then, he (Kaczynski) has become emotional."

Warsaw University political scientist Anna Materska-Sosnowska told AFP the conflict was based in a "vendetta".

"If you look at Kaczynski's reaction to Tusk's re-election -- his insults and degradation, accusing Tusk of betraying Poland -- it's all very personal and shows Kaczynski's inability to put the past to rest," she said, adding: "It's made Poland's diplomatic policy look ridiculous."

The PiS insists it wants Poland to remain rooted firmly in the EU, but it has rejected any notion of the "multi-speed EU" favoured by powerhouse states Germany and France as a means to deepen ties at different speeds.